When I visit my doctor (sleep specialist) for a review of my CPAP effectiveness, he reviews a summary report prepared by office staff. In it are average stats from the past month, with no details from the nightly graphs.
I've been using CPAP therapy for 3.5 years, and 8 cm was all I needed for most of that time. Then, for some reason, the AHI's increased from an average of 3 per night to 8, with nearly half of those being CA's (appearing for the first time.) Cheyne Stokes began to appear for the first time, also with no health explanation.
My doctor's response was to lower the pressure, which left no change in AHI. Several months later, AHI events nearly doubled again, with many nights resulting in 25 events, including CA's. My doctor increased the pressure to 12 cm. No change in AHI's, and no word from my doctor about trying something else.
Thankfully, I found this forum and read the advice about turning off the EPR control, which I did. For the weeks since doing so, the AHI's have been under 5 with virtually no CA's and no Cheyne Stokes
To those of you who articulate these kinds of issues on this forum - a huge THANK YOU!
It's obvious that I'm going to have to control my CPAP machine myself. To that end, can someone please explain exactly what Sleephead data is used to determine optimum pressure?
Again, thank you!
It's an ongoing process. Basically you have to know what is going on and to recognize situations. The nutshell version is you raise EPAP to manage Obstructive events, you raise PS/Pressure support and as a result IPAP to manage Hypopneas and Flow Limits. This is Standard BiLevel titration. With EPR we have to adjust pressures with EPR changes to accomplish this. With Central events with a CPAP or a bilevel without backup in general you lower Pressure to lower Centrals, also an increase in Pressure variation (EPR or Pressure support or algorithm based pressure changes) all also increase Central Events. So if Centrals are present you have a real balancing act to complete. When the standard things don't work, all of us are different, you experiment to see how you react and go with what works. You also need to be aware of how the different algorithms differ to understand how that will affect the person.
Because you mention EPR and CSR reporting I am assuming you have a ResMed machine? If you post the specific model of machine I could make more specific comments.
In any case your situation sounds similar to mine. I am not a medical professional, but I use a ResMed AirSense 10 AutoSet, and my apnea has been mixed central and obstructive. At the worst the CA to OA ration has been as high as 5 to one. However, overall I have been managing to keep AHI under 5. What has worked for me is do everything possible to keep pressure down. As you have found out, turning off EPR helps because the machine does not have to raise IPAP higher to address apnea that is occurring during or in the transition between IPAP and EPAP (inhale and exhale). I still use EPR at 3, but on Ramp Only. Next I narrowed the range between max pressure and minimum pressure by keeping the maximum as low as possible and by only increasing the minimum. When it got to the point where they were nearly the same, I simply switched to a fixed CPAP pressure. When I was using EPR and a wide max min range, pressures were going as high as 15 cm, and I was seeing lots of CA and some CSR. Now I have gone 6 weeks with a fixed pressure of 11 cm and AHI has a median of about 1.7. I posted a while back about my journey to fixed CPAP mode in this thread. I have been trying to determine if a bit lower or higher than 11 is better, but so far I have not found anything better. Once you go to fixed pressure about all you can do is try small steps and see what you get.
Increasing CSR indications can be a signal that there are some heart issues affecting blood circulation. It is something you should discuss with your GP if they continue.
SleepyHead is very useful in determining when and at what pressure during the night you are having central apnea and CSR events. I also find if you look at the Minute Ventilation value it is good indicator of breathing stability. Central apnea and CSR are most often the result of breathing instability when asleep. You can see it as a roller coaster ride effect in Minute Ventilation.
Hope that helps some,
Thank you, Sierra. Our cases do sound similar, and I, too, use an AirSense 10 AutoSet.
My current settings are a low of 7 and high of 12 cm. For the past three weeks, AHI has run between 1.3 and 4.7. The CA's have almost disappeared, although a few do show up on some nights. No CSR's at all, and we ruled out any heart issue. (But, thanks for the caution!)
If I'm understanding your method correctly, I should increase the minimum pressure, while lowering the high pressure slightly. This would hopefully bring them to a fixed point, lower than my current high. I assume this will take some trial and error over several months, and be a bit of an experiment.
How much higher would you suggest trying the low and high to start out?
Don't know how much your experience with this process (described in your indicated posts) may be generalized to others, but your thinking makes sense to me. I'd like to try it.
Thank you, again!
It would be best to start with posting a screenshot from SleepyHead. You need a PC or Mac with a SD card reader. The software is a free download. There is a basic manual at this link. Basically what I do is look to see what is happening and what events are occurring at higher pressures. If there are more CA events there, then there may be a benefit in lowering pressure. However it is not really that cut and dried. If you see breathing instability with waxing and waning cycles in flow, as well as ups and down in Minute Ventilation, that can be an indication of central related instability. That instability can in turn cause hypopnea and obstructive apnea. About all you can do is zoom in on events that occur at higher pressure and try to figure out what the initiating factor is.
On the low pressure side it is usually simpler. Look for areas when you are getting OA events. If it is when the pressure is at minimum or near it, then there tends to be benefit in increasing minimum pressure. A higher minimum can avoid those events, instead of letting them occur to trigger an auto response to increase pressure. This is a bit of an iterative process and I find it takes a minimum of a week at one setting to determine if it is an improvement or not.
But it would be best to post a SH chart for comments. With the Daily Detail at full screen just press the F12 on a PC and a screen shot image will be saved to a directory which will display briefly in the bottom right. To post it here, open a new message with the Write a Reply button to get a full width window, then drag the saved .png file from Windows Explorer to the open body of the message.
